The Student and The Barometer

Some time ago I received a call from a colleague. He was about to give a student a zero for his answer to a physics question, while the student claimed a perfect score. The instructor and the student agreed to an impartial arbiter, and I was selected.

I read the examination question: "Show how it is possible to determine the height of a tall building with the aid of a barometer." The student had answered: "Take the barometer to the top of the building, attach a long rope to it, lower it to the street, and then bring it up, measuring the length of the rope. The length of the rope is the height of the building."

The student really had a strong case for full credit since he had really answered the question completely and correctly! On the other hand, if full credit were given, it could well contribute to a high grade in his physics course and certify competence in physics, but the answer did not confirm this.

I suggested that the student have another try. I gave the student six minutes to answer the question with the warning that the answer should show some knowledge of physics. At the end of five minutes, he hadn't written anything. I asked if he wished to give up, but he said he had many answers to this problem; he was just thinking of the best one. I excused myself for interrupting him and asked him to please go on.

In the next minute, he dashed off his answer, which read: "Take the barometer to the top of the building and lean over the edge of the roof. Drop the barometer, timing its fall with a stopwatch. Then, using the formula x=0.5*a*t^2, calculate the height of the building." At this point, I asked my colleague if he would give up. He conceded, and gave the student almost full credit.

While leaving my colleague's office, I recalled that the student had said that he had other answers to the problem, so I asked him what they were. "Well," said the student, "there are many ways of getting the height of a tall building with the aid of a barometer. For example,if the sun is shining you could measure the height of the barometer, then set it on end and measure the length of its shadow. Then you measure the length of the skyscraper's shadow, and thereafter it is a simple matter of proportional arithmetic to work out the height of the skyscraper.

"Fine," I said, "and others?"

"Yes," said the student, "there is a very basic measurement method you will like. In this method, you take the barometer and begin to walk up the stairs. As you climb the stairs, you mark off the length of the barometer along the wall. You then count the number of marks, and this will give you the height of the building in barometer units." "A very direct method."

"Of course. If you want a more sophisticated method, you can tie the barometer to the end of a string, swing it as a pendulum, and determine the value of g [gravity] at the street level and at the top of the building. From the difference between the two values of g, the height of the building, in principle, can be calculated."

"On this same tack, you could take the barometer to the top of the building, attach a long rope to it, lower it to just above the street, and then swing it as a pendulum. You could then calculate the height of the building by the period of the precession".

"Finally," he concluded, "there are many other ways of solving the problem. Probably the best," he said, "is to take the barometer to the basement and knock on the superintendent's door. When the superintendent answers, you speak to him as follows: 'Mr. Superintendent, here is a fine barometer. If you will tell me the height of the building, I will give you this barometer."

At this point, I asked the student if he really did not know the conventional answer to this question. He admitted that he did, but said that he was fed up with high school and college instructors trying to teach him how to think.

The name of the student was Niels Bohr, who later received the Nobel prize for Physics.

Tests Before Having Children
FOLLOW THESE 14 SIMPLE TESTS BEFORE YOU DECIDE TO HAVE CHILDREN:
 Test 1

Women: to prepare for maternity, put on a dressing gown and stick a beanbag down the front. Leave it there for 9 months. After 9 months remove 5% of the beans.

Men: to prepare for paternity, go to a local chemist, tip the contents of your wallet onto the counter and tell the pharmacist to help himself. Then go to the supermarket. Arrange to have your salary paid directly to their head office. Go home. Pick up the newspaper and read it for the last time.

Test 2

Find a couple who are already parents and berate them about their methods of discipline, lack of patience, appallingly low tolerance levels and how they have allowed their children to run wild. Suggest ways in which they might improve their child's sleeping habits, toilet training, table manners and overall behavior. Enjoy it. It will be the last time in your life that you will have all the answers.

Test 3

To discover how the nights will feels:

1. Walk around the living room from 5pm to 10pm carrying a wet bag weighing approximately 4 - 6kg, with a radio turned to static (or some other obnoxious sound) playing loudly.

2. At 10pm, put the bag down, set the alarm for midnight and go to sleep.

3. Get up at 12pm and walk the bag around the living room until 1am.

4.Set the alarm for 3am.

5. As you can't get back to sleep, get up at 2am and make a cup of tea.

6. Go to bed at 2.45am.

7. Get up again at 3am when the alarm goes off.

8. Sing songs in the dark until 4am.

9. Put the alarm on for 5am. Get up when it goes off.

10. Make breakfast. Keep this up for 5 years.

LOOK CHEERFUL.


Test 4

Dressing small children is not as easy as it seems:

1. Buy a live octopus and a string bag.

2. Attempt to put the octopus into the string bag so that no arms hang out.

3. Time allowed for this: 5 minutes.

Test 5

Forget the BMW and buy a practical 5 door wagon. And don't think that you can leave it out on the driveway spotless and shining. Family cars don't look like that.

1. Buy a chocolate ice cream cone and put it in the glove compartment.

2. Leave it there.

3. Get a coin. Insert it into the cd player.

4. Take a box of chocolate biscuits; mash them into the back seat.

5. Run a garden rake along both sides of the car.

Test 6 Get ready to go out

1. Wait

2. Go out the front door

3. Come back in again

4. Go out

5. Come back in again

6. Go out again

7. Walk down the front path

8. Walk back up it

9. Walk down it again

10. Walk very slowly down the road for five minutes.

11. Stop, inspect minutely and ask at least 6 questions about every piece of used chewing gum, dirty tissue and dead insect along the way.

12. Retrace your steps

13. Scream that you have had as much as you can stand until the neighbors come out and stare at you.

14. Give up and go back into the house.

15. You are now just about ready to try taking a small child for a walk.

Test 7

Repeat everything you say at least 5 times.

Test 8

Go to the local supermarket. Take with you the nearest thing you can find to a pre-school child. A full-grown goat is excellent. If you intend to have more than one child, take more than one goat.

Buy your weeks groceries without letting the goat(s) out of your sight. Pay for everything the goat eats or destroys. Until you can easily accomplish this, do not even contemplate having children.

Test 9

1. Hollow out a melon

2. Make a small hole in the side

3. Suspend the melon from the ceiling and swing it side to side

4. Now get a bowl of soggy cornflakes and attempt to spoon them into the swaying melon while pretending to be an aeroplane.

5. Continue until half the cornflakes are gone.

6. Tip the rest into your lap, making sure that a lot of it falls on the floor.

7. You are now ready to feed a 12-month old child.

Test 10

Learn the names of every character from the Wiggles, Barney, Teletubbies and Disney. Watch nothing else on television for at least 5 years.

Test 11

Can you stand the mess children make? To find out:

1. Smear peanut butter onto the sofa and jam onto the curtains

2. Hide a fish behind the stereo and leave it there all summer.

3. Stick your fingers in the flower beds and then rub them on clean walls.

4. Cover the stains with crayon.

5. How does that look?

Test 12

Make a recording of someone shouting "Mummy" repeatedly. Important: no more than a 4 second delay between each Mummy - occasional crescendo to the level of a supersonic jet if required. Play this tape in your car, everywhere you go for the next 4 years. You are now ready to take a long trip with a toddler.

Test 13

Start talking to an adult of your choice. Have someone else continually tug on your shirt hem or shirt sleeve while playing the Mummy tape listed above. You are now ready to have a conversation with an adult while there's a child in the room.

Test 14

Put on your finest work attire. Pick a day on which you have an important meeting. Now:

1. Take a cup of cream and put 1 cup of lemon juice in it

2. Stir

3. Dump half of it on your nice silk shirt

4. Saturate a towel with the other half of the mixture

5. Attempt to clean your shirt with the same saturated towel

6. Do not change, you have no time.

7. Go directly to work

You are now ready to have kids. ENJOY!!!